Traditionally, sealants such as caulk are applied within a seam, gap, or joint as way to fill the gap. However, with certain applications, some issues may arise. For example, in one known method for applying a sealant, such as sound control sealant (SCS), an operator uses a hand-gun containing a cartridge with a straight tip nozzle to apply sealant to fill in a gap, such as a gap formed at the top and bottom of a sheet of drywall, during installation of the drywall.
The straight tip is cut at an angle to form an opening. The angle and diameter of the opening are determined by the operator before cutting the tip and are based on the size of the gap to be filled, since the operator wants to both use the gap to guide the tip and also maximize the amount of sealant pumped into the gap while the operator moves the hand-gun along the length of the gap.
In filling a high gap, for example where drywall meets the ceiling, the operator typically uses a step stool, ladder, or lift in order to bring the straight tip in contact with or near the high gap. In filling a lower gap, for example where drywall meets the floor, the operator typically needs to bend over and drag the hand-gun backward over the lower gap, which makes it difficult to pressure pack the sealant into the lower gap.
Moreover, there is often confusion as to when the sealant should be applied to fill in a gap. For example, during the installation of the drywall, many local codes do not have clear application specifications for the application of SCS in filling gaps between sheets of drywall. Some operators apply the SCS before the drywall sheet is installed, some apply after the drywall sheet is installed, and some apply both before and after the drywall sheet is installed. Additionally, some operators apply the SCS simultaneously during the installation of the drywall sheets and some operators apply the SCS independent of installing the drywall sheet, as long as the SCS has not hardened.
Sometimes upon applying the sealant, for example in cases when the SCS is applied after the drywall sheet is installed, the operator may need to go back to finish a bead of sealant by removing any excess sealant. The operator may use a trowel or tool, such as a caulk finishing tool manufactured by the DAP Co. of Baltimore, Md., to finish and clean-up any excess sealant. This two-step process is rather cumbersome and requires additional time in order to apply and then finish the sealant.
Moreover, when sealant is applied with a straight tip nozzle, it is often difficult to control the amount of sealant applied. The straight tip is often not capable of providing sufficient back pressure against a bead of sealant as the sealant is dispensed through the straight tip. The sealant often comes out of the straight tip at atmospheric pressure and flows freely into and out of the gap, which is the path of least resistance. Typically, the sealant will not compress deep into the gap, since this is a path of more resistance.
Sometimes, when applied using a straight tip, the sealant results in a partially filled gap with a curtain of sealant at the mouth of the gap, which may only lightly attach to the top of the gap. If air tight, then this thin curtain of sealant may not be sufficient for sealing the gap. For example, in some applications the thin curtain may reflect but not absorb sound because of its low mass. Over time, the thin curtain of sealant may slump or sag due to its own weight and viscosity conditions, along with a lack of pressure adherence in the area at which the sealant hangs from at the top of the gap. Additionally, the sealant may shrink a certain amount over time due to temperature changes or variations in moisture. The slump and shrinkage of sealant within a partially filled gap may cause an air gap or opening in the gap to occur, which allows for the direct transmission through the gap, such as the transmission of sound waves through the gap.
Sometimes, when an operator is applying sealant with a straight tip, the hand-gun is often dragged away from the bead of sealant and a pulling or stringing of the bead may occur which may cause a discontinuous bead with air paths along the top surface of the bead. In all methods for applying sealant in which a straight tip is used, the operator may have difficulty visually sensing if the gap is sealed and filled with sealant because the operator may not be able to see the back side of the bead of sealant, in addition to possibly having difficulty seeing the front of the bead of sealant. This may result in the improper application of sealant within the gap, requiring the sealant to be reapplied at a significant expense, in order to pass testing, such as sound testing for SCS.
The application of sealant may require a second step for finishing or clean-up of excess sealant. While filling the gap with sealant from a straight tip, the sealant often under-fills or over-fills the gap, resulting in a poor finished look. The sealant may spill out of the gap and make an unsightly mess, which should be wiped off, resulting in time lost and extra cost associated with having an operator back track and going over a bead of sealant a second time. This not only results in two steps, but also results in excess sealant being applied and thus having to be disposed of.
Additionally, the two-step process typically does not work well when using a long hose or tube assembly, known as a “wand,” attached to a bulk backpack dispenser for dispensing sealant. For example, the wand is often used to apply sealant to seal a gap located at a height which is difficult for the operator to reach with his hands. Therefore, in order to perform the finishing step, the operator would then have to use a ladder or chair to reach the sealant within the gap and finish the bead of sealant.
As a result, it would be desirable to have a one-step process wherein the sealant is applied and finished in a single operation. Additionally, it would also be desirable to apply the sealant in a way which minimizes or at least reduces the amount of excess sealant within a gap, thereby reducing or eliminating the need for a finishing step. Additionally, it would also be desirable for the operator to be able to visually sense if the gap is sealed and filled with sealant.